There are fifteen orders of magnitude separating the scale of our daily lives from that of nuclear matter – nuclei, nucleons and quarks – the playing field of radioactive phenomena. The living matter of a tree, which can reach 20 or 30 metres into the air, is comprised of cells containing large molecules formed of minuscule atoms with a radius of several billionths of a metre. As small as they may be, atoms are some 100,000 times larger than the nucleons which agglomerate to form the subatomic nuclei. The Russian doll process has not yet finished: nuclei are in their turn made up of quarks.